Diastolic dysfunction (i.e., insufficient expansion of the left ventricle during the diastolic phase) and general deterioration of the left ventricular performance are very common problems, affecting about 5 million people in the US alone. The problems can be triggered by a myocardial infraction or develop slowly over time. More background data on congestive heart failure can be found on the internet at: http://healthlink.mcw.edu/article/928348606.html and many other medical sources.
Prior art treatment can be classified generally into three methods: surgery to change the shape of the left ventricle, wrapping the heart in an elastic net, or introducing a reinforcing structures via a catheter into the left ventricle. The first two methods require extensive surgery. The prior art minimally invasive or percutaneous procedures such as disclosed by US patent applications 2005/0015109; 2004/0243170; 2004/0249408 and 2006/0025800 addressed the need of strengthening the heart wall to resist remodeling and enlargement due to systolic pressure, but do not improve diastolic expansion to allow better filling of the left ventricle with blood. In many cases prior art methods actually sacrifice diastolic function in exchange for preventing the abnormal enlargement of the left ventricle that often follows myocardial infraction. For example, wrapping the heart in an elastic net will assist systolic action and will limit left ventricle enlargement, but will interfere with diastolic function as it will require more force to expand the left ventricle and stretch the net. The same is true for any rigid internal reinforcement.